[test] [linux] define PR_SET_PTRACER constants if the system does not provide them
[test] [linux] define PR_SET_PTRACER constants if the system does not provide them

Android API <= 16 header do not have these symbols defined, but the kernel does support the
relevant calls. And in general, since these calls are on a best-effort basis, it won't hurt even
if we try to run in on a really ancient kernel.

git-svn-id: 4c4cc70b1ef44ba2b7963015e681894188cea27e@275393 91177308-0d34-0410-b5e6-96231b3b80d8

apple/swift-lldb,apple/swift-lldb,llvm-mirror/lldb,llvm-mirror/lldb,llvm-mirror/lldb,llvm-mirror/lldb,apple/swift-lldb,apple/swift-lldb,llvm-mirror/lldb,apple/swift-lldb,apple/swift-lldb